The present invention pertains to a control system for the transmission of a vehicle and particularly an electrical control for such purpose.
Vehicle gear shifts typically take the form of a control lever either extending from the right hand side of the steering column behind the steering wheel or a floor mounted gearshift lever. Most vehicles now include, as a standard feature, an automatic transmission with a control which allows the selection of different gears as well as the usual park, reverse, neutral and standard automatically shifted drive position. Such controls thus allow the operator to select lower gears if desired for certain uses.
Although the mechanical shifting mechanism provided for controlling either manual or automatic transmissions have proven themselves over years of use, with today's modern vehicles where electronics are becoming more sophisticated and electronic systems for vehicles have reached a level of liability and sophistication which has been unsurpassed in previous vehicle applications; there exists a need for a transmission control system which can be achieved electrically. It is necessary that any such control provides the driver with the confidence of prior mechanical gearshift levers which required an incremental physical movement of a control element to achieve gear changes and one with a physically gripable handle.
Push button electrical control systems for vehicles have not met with great popularity even though they were introduced to the automotive industry as early as in the 1950's with the Edsel vehicle in which mechanical push button switches were located in the steering wheel hub. Other push button control systems have also been suggested as disclosed in U.S. Pat. Nos. 4,922,769 and 4,884,057. U.S. Pat. No. 3,766,793 discloses a rotary mechanical shift dial which is coupled by means of a cable to the vacuum control transmission shifting mechanism. U.S. Pat. No. 3,326,315 discloses a combined transmission shifter and ignition key assembly which can be located on the dashboard or in a console between the vehicle seats. The shifting mechanism includes a mechanical cable connection to the vehicle transmission.
Thus, today, although mechanical and/or electrical push button controls for transmissions have been proposed, they have not gained a foothold in the automotive industry. As vehicles become more sophisticated and ergodynamically designed for operator convenience and safety, the ability to provide a vehicle purchaser with optional or selectable vehicle features is desired. Thus, many vehicle operators would prefer the transmission control located in either a console between the seats or on the steering column. Others may prefer the location of the transmission control at another location such as in the dash area. To provide such selectability with mechanical controls is virtually impossible for the mass produced car market even though the ability to present the customer with such flexibility would be a significant selling feature. Thus, there exists a need for a reliable and acceptable transmission control which electrically controls a transmission and which allows the purchaser to select a convenient location for such control.